J. Nannoplankton Res. 30 (1), 2008, pp.35-38 © 2008 International Nannoplankton Association, Inc.
ISSN 1210-8049 Printed by Cambridge University Press, UK35

Scyphosphaera porosa Kamptner, 1967 rediscovered in theplankton
Jeremy R. Young

Palaeontology Department, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK; j.young@nhm.ac.uk
Manuscript received 19th December, 2007; revised manuscript accepted 9th March, 2008

Abstract Scyphosphaera porosa was described by Kamptner (1967) from Late Quaternary sediments obtainedby the Challenger Expedition, but has not since been recorded. A single coccosphere of this species has been discovered on a filter from the lower photic zone, collected during Atlantic Meridional Transect Cruise 14 from near the typelocality. The new specimen proves that this is a distinctive extant species, but possibly with closer affinity to Pontosphaera multipora than Scyphosphaera apsteinii.

Keywords Scyphosphaera, lower photic zone, coccolithophores
1. Introduction
Scyphosphaera is one of the more striking of the extant
coccolithophores, producing large dimorphic coccospheres,with plate-like body coccoliths and bowl-like equatorial‘lopadoliths’. Only one extant species of Scyphosphaera, S.
apsteinii, is recognised in recent syntheses of the extant
coccolithophore flora (e.g. Young et al., 2003; Jordan etal., 2004), although a high diversity of Neogene species
has been described (see reviews by Aubry, 1990; Siesser,
1998; Young, 1998).
Whilst examining a plankton filter-sample from theSouth Atlantic, collected during Atlantic Meridional Transect (AMT) Cruise 14, a beautiful and very unusual
Scyphosphaera specimen was observed. Technically, thisis not a new species, since a literature review revealed thatit had previously been described by Kamptner (1967) from
Holocene sediments, but it does not appear to have been
observed in the plankton before, and so this note briefly
records it as an addition to the known biodiversity of extant
coccolithophores.
2. Structure of Scyphosphaera coccoliths
As discussed by Romein (1979), Theodoridis (1984) andAubry (1990), Pontosphaera, Scyphosphaera and Helicosphaera coccoliths all have rather similar structure, andthey are all included in the Zygodiscales in recent classifications (Young & Bown, 1997; Young et al., 2003). In eachcase, they are formed of three main sets of elements: anouter flange, proximal plate and distal blanket. The outerflange is formed of anticlockwise-imbricated elements, andin Helicosphaera is modified into a spiral flange. It is
formed of crystals with sub-vertical c-axes, that is, V-units,
which are dark in crossed-polars in plan view. The proximal plate is formed of radial elements and the blanket of amass of small, apparently discrete, units. Both the blanket
and the proximal plate are formed of crystal units with subradial calcite c-axes, that is, R-units, and are in fact continuous with each other (Henriksen et al., 2004; Young etal., 2004).

In Scyphosphaera apsteinii lopadoliths, the outer flangeof V-units forms a narrow layer around the outside of thecoccolith, the elements show strong anticlockwise imbrication in the lower third or so of the coccolith, then continue vertically to the top of the coccolith (Pl.1, fig.6). The
R-units form the proximal plate of radial elements, whichhave a much less regular appearance on their distal side,and extend up the inside of the lopadolith wall, usually continuing to the crest of the wall. The wall thus has a twolayered construction (Pl.1 figs 7, 8, and see description ofKamptner, 1967).
3. Material and methods
The specimen was observed by light microscopy (LM) ofa filter sample, collected by Timothy Adey (NationalOceanography Centre, Southampton), during Atlantic
Meridional Transect Cruise 14 from the tropical South Atlantic in early summer, 2004. The sample was from conductivity-temperature-depth cast 26, 120m water-depth,
24.23˚S, 25.00˚W. The sample was collected on a Nucleopore-type polycarbonate filter. Cruise and sample details
are documented in Holligan et al. (2004).

Figure 1: Map of the South Atlantic showing the location of Challenger
Station 338, type locality of Scyphosphaera porosa, 50km and Station
AMT14-CTD26, from which the new specimen was collected

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Young

For LM, a portion of the filter was permanentlymounted on a glass slide using low viscosity Norland Optical Adhesive No.74. Polycarbonate filters are not idealfor LM as they are optically translucent, rather than transparent, and the micropores disrupt images. In practice, thismeans it is not possible to use bright-field or phase-contrast illumination. In crossed-polars, however, the filters
behave as single, low-birefringence crystals. By rotating
the stage to the position where the filter goes into extinction, coccolithophores can usefully be studied. The sample
was studied on a Zeiss Axioplan transmitting light-microscope, equipped with a Leica Firecam 280 camera for digital imaging. Comparative specimens of Scyphosphaera
apsteinii were imaged on a Phillips XL-30 FEG scanningelectron microscope (SEM).
4. Observations
The AMT sample contains a diverse lower-photic assemblage, including Florisphaera profunda, Gladiolithus flabellatus, Algirosphaera robusta, Hayaster perplexus,Reticulofenestra sessilis, Scyphosphaera apsteinii, Syracosphaera anthos, S. lamina and S. bannockii. The sample
has been extensively studied by both SEM and LM. In LM,a single, very unusual Scyphosphaera specimen was observed, as illustrated in Plate 1, fig.1. The coccosphere isformed of five equatorial lopadoliths (high-sidedmuroliths) and ca.40 body-coccoliths. Excluding thelopadoliths, the coccosphere is 28µm in diameter. Thelopadoliths are straight-sided, flaring distally, 15-20µm
high, with a basal width of 6-7µm and distal width of 1015µm. The body coccoliths are irregularly elliptical in planview, 5-8µm long and 4-5µm wide, with two or three ringsof large (ca.0.5µm) pores.
When examined in crossed-polars with a gypsum plate,the lopadoliths can be seen to be constructed of two cycles
of units. An outer cycle of elements with c-axes oriented
parallel to the length of the lopadoliths (V-units) formsmost of the wall. An inner cycle with c-axes oriented perpendicular to the length of the lopadoliths (R-units) forms
the base and an inner layer of the wall, extending a quarterto half the way up the wall.
5. Interpretation
Numerous Cenozoic species of Scyphosphaera have been
described, particularly from the Late Neogene, but it has
generally been thought that there is only one extant species,
Scyphosphaera apsteinii, possibly with a sub-taxon, S. apsteinii f. dilatata. My own observations of Scyphosphaera
specimens, from both plankton samples and culture experiments, fully confirm this. While every S. apsteinii coccosphere is different, they share numerous common
characteristics, and clearly differ from the specimen observed here. The lopadoliths of S. apsteinii are typicallybroad and distinctly barrel-shaped (Pl.1, figs 4-7). In crosssection, they have thick walls, with the inner cycle of Runits extending to the top of the coccolith (Pl.1, figs 7, 8).
This contrasts markedly with the observed specimens inwhich the lopadoliths are straight-sided, thin-walled and inwhich the R-units only extend a short distance up the coccolith. Just as strikingly, the S. apsteinii coccospheres usually only have 10-15 body coccoliths with an irregular
scatter of minute pores in the central-area (Pl.2, figs 4, 5),in contrast to the much more numerous body coccoliths
with large pores of the observed specimen.
The illustrated specimen (Pl.1, figs 1, 2) is clearly notS. apsteinii. A review of the numerous other species thathave been described (see reviews in Aubry, 1990 andSiesser, 1998) revealed that S. porosa Kamptner, 1967 isbased on essentially identical lopadoliths, as shown by thefigures from Kamptner (1967) reproduced here (Pl.1, figs
3, 4). They show the same simple, flaring shape, with large
pores in the base, and are similar in size. Kamptner (1967)
quotes a size-range of 15-21.7µm high; the lopadoliths on
the new specimen are 15-20µm high. Kamptner (1967) also
described, in detail, the appearance of the specimens incross-polarised light and with the gypsum plate and, specifically, the fact that the base and wall show different behaviour. Finally, it is noteworthy that Challenger Station
338 was located in the South Atlantic at 21.25˚S, 14.03˚W,
and so remarkably close to the site from which this newspecimen was collected (Figure 1).
Kamptner (1967) only observed isolated lopadoliths ina sediment-sample, so he did not have any data on the associated body coccoliths. Nonetheless, the similarity of thelopadoliths is so striking that it is clear that the observed
specimen is a coccosphere of S. porosa, rather than of anundescribed species.
Material from the Challenger Expedition is archived in
the Natural History Museum, so it was possible to makenew smear-slides from the ooze recovered from Station
338. However, no specimens of S. porosa were found. This
is not entirely surprising, as it is evident that Kamptner(1967) only found a few specimens in the course of his extended study of the sample.
6. Discussion
Given the intensive studies that have been carried out on
extant coccolithophores, including South Atlantic samples,
it is rather surprising to find a large and very distinctive
species in the plankton for the first time. Either Scyphosphaera porosa is a very rare species, possibly confined to
the South Atlantic or, conceivably, it is not a discrete
species, but rather a rarely-expressed life-cycle phase of
Pontosphaera multipora, which is a rather rare and variable species. This interpretation is suggested by the similarity of the body-coccoliths to those of P. multipora. Since
I only have LM observations on a single specimen, it is notpossible to definitively distinguish between these two possibilities, but in the absence of any positive evidence that it
is a life-cycle phase, I suggest S. porosa should be regarded
as a discrete species.
An unusual aspect of S. porosa is that the inner wallcycle of R-units only extends part of the way up thelopadolith. Not just S. apsteinii, but also the diverse range

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Living Scyphosphaera porosa

Plate 1LM and SEM micrographs of Scyphosphaera coccoliths. All scale-bars = 5µm
S. porosa (LM) from Kamptner (1967). Specimens fromChallenger dredging, Station 338

S. porosa coccosphere (LM, crossed-polars), on filter from Sample AMT14 CTD26
Line-drawing of one of the lopadoliths from the new S. porosa specimen

Coccosphere of S. apsteinii (SEM) from Hawaii, HOTS station (Image 217-83)

S. apsteiniii lopadolith (SEM) distalview, from culture (Image 228-46)

S. porosa line-drawings
from Kamptner (1967)

S. apsteinii coccosphere (SEM) from culture, showinglopadolith morphology in side view (Image 228-61)

S. apsteinii lopadoliths (LM) in plan and side views. Both specimensfrom Sample ODP 154-925B-1-1, 4.5-5.5cm (nannofossil zone NN21)

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Youngof Neogene Scyphosphaera species, show the R-units extending to the crest of the coccolith. To verify this, several
Neogene samples with high concentrations of Scyphosphaera coccoliths were re-examined, and no specimens
with restricted R-unit cycles similar to those of S. porosawere seen. So, S. porosa is a rather anomalous Scyphosphaera species, which possibly makes affinity with Pontosphaera more likely.
7. Conclusion
A single coccosphere of the large species Scyphosphaera
porosa has been observed on a plankton filter from theSouth Atlantic lower photic zone. It is possible that this isan aberrant Pontosphaera, rather than a true Scyphosphaera, but in either case it provides another example ofthe continuing trend of new observations of rare, patchilydistributed, lower-photic species, as documented by, for example, Jordan & Chamberlain (1993), Young & Andruleit(2006) and Bollmann et al. (2006).
Acknowledgements

The specimen imaged here was observed on a portion of filter
collected by Tim Adey (U. Southampton). Comparative specimens of S. apsteinii imaged here were studied in the context ofcollaborative research with Dr. Ian Probert (SBR Roscoff; fundedby the French ANR, ‘BOOM project’) and Dr. Jackie Lees (UCL;funded by the UK NERC Research Grant NE/C510508/1, ‘nannofractions project’). Ric Jordan and Jackie Lees made usefulsuggestions during review of the manuscript.

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